1. Technical Field
The present invention relates to a technology of searching for and retrieving an image which is similar to an input image, from among images registered in a database or the like.
2. Related Art
Recently, in the business world considerable emphasis has been placed on enhanced security of information and handling of information, in view of compliance with regulations or protection of personal information. For example, in response to audits or the like, companies are required to disclose information based on which their business has been performed. It is therefore necessary for companies to record, as log data, and manage the access to their services so that they can specify the person who has processed information, the kind of information and process which have been used, and so on.
In view of such a trend, there has been proposed a system in which, in the event of actions such as output of a document by means of copying, printing, facsimile transmission, or the like, and electronic input of a paper document by means of scanning, image data which are output or input at the time of these actions are stored as log data together with the date, an operator name, and so on, and then, if at a later time data leakage concerning a certain document is suspected, a document which is the same as the certain document is searched through the log data, thereby specifying a source of leakage or the like.
In order to realize the above system, an image corresponding to a target document must be searched and retrieved from the log data. Here, very high operability can be achieved if search can be performed by means of the image itself which is obtained by scanning the target document as a search condition, rather than the user entering detailed information such as a search keyword and so on. For any purposes other than the security purpose described above, it would be similarly advantageous if a user could search through an image database and retrieve an image similar to a scanned image.